The invention relates to a drive arrangement for a retractable folding roof, in particular for a folding top of cabriolets. The drive arrangement includes a pivot drive for a front folding-roof part. The front folding-roof part is mounted on the vehicle body through the use of lateral pillars via two double-acting operating cylinders which are each supported, by one of their ends, on the body and, by their other end, in an articulated manner on a lever arm of that pillar of the front roof part which is assigned to it. The drive arrangement further includes a movement coupling for coupling a rear roof part to the front roof part during common pivot-movement phases using a lever mechanism. The lever mechanism includes, on both sides of the folding roof, a crank-rocker linkage which is mounted on the assigned pillar and by means of whose rocker end an assigned side leg of the rear roof part can be made to pivot. With the pivot drive of the rear roof part relative to the front roof part, by means of which pivot drive the lever mechanism can be moved relative to the pillars, in each case one double-acting operating cylinder is articulated on a lever of the lever mechanism of the two pillars.
Such a drive arrangement is already known for folding tops of cabriolets, e.g. from German Patent document DE 39 01 051 C2. For the pivot drive of the front and rear folding-top parts during opening and closing of the folding top, provision is made here for altogether the use of four operating cylinders. Two of these operating cylinders are overhung-mounted on the folding-top pillar assigned to them. They form the pivot drive for relative pivoting of the rear folding-top part with respect to the front folding-top part. For these overhung-mounted operating cylinders, provision has to be made for a considerable fitting and pivot-movement space, which is not available in design terms in each folding-roof concept. Furthermore, the two operating cylinders cause a considerable amount of extra weight and a considerably higher degree of outlay, in terms of control, mounting and thus cost, than two operating cylinders for the folding-top pillars.
Furthermore, German Patent document DE 39 37 764 C1 discloses a drive arrangement in which synchronously working operating cylinders are provided for the pivot drive of front and rear folding-top parts.
Here, the two folding-top pillars of the folding top are driven by a main-link pair. The main links can be pivoted by an associated operating cylinder, with the interposition of a toothed-wheel gear mechanism. In order to also permit, via the two operating cylinders acting on the folding-top pillars, the relative pivoting of the rear folding-top part with respect to the front folding-top part, the toothed-wheel gear mechanisms assigned to the main links can each be blocked via a hook locking member. The operating cylinders are supported on the body via a rocker-like mount. The rocker-like mount is movement-coupled, via a rod-type mechanism, to the associated lateral leg of the rear folding-top part.
The main drive arrangement is likewise extremely high in outlay in technical terms and correspondingly expensive. In addition, it presupposes a framework concept in which the main links are mounted in the vicinity of the main pivot axis of the folding top.
There is therefore needed a drive arrangement designed such that, for the pivot drive of the folding roof or folding top, only two operating cylinders assigned to the lateral pillars are required. The drive arrangement should have an overall compact configuration which is favorable in terms of weight and cost.
These needs are met according to the present invention by a drive arrangement for a retractable folding roof having a pivot drive for a front folding-roof part. The front folding-roof part is mounted on the vehicle body through the use of lateral pillars via two double-acting operating cylinders which are each supported, by one of their ends, on the body and, by their other ends, in an articulated manner on a lever arm of an assigned front roof part pillar. The drive arrangement further includes a coupling for movably coupling a rear roof part to the front roof part during common pivot-movement phases using a lever mechanism. The lever mechanism includes, on both sides of the folding roof, a crank-rocker linkage which is mounted on the assigned pillar. By means of a rocker end of the linkage, an assigned side leg of the rear roof part can be made to pivot. With the pivot drive of the rear roof part relative to the front roof part, by means of which pivot drive the lever mechanism can be moved relative to the pillars, in each case one double-acting operating cylinder is articulated on a lever of the lever mechanism of the two pillars. The operating cylinders, i.e., hydraulic cylinders, serving for the pivot drive of the front roof part are also used for the relative pivoting of the rear roof part. For this purpose, the operating cylinders are connected to the lever arm of the pillar assigned to them via a rotary-slide articulation which can be blocked for common pivot-movement phases of the front roof part and the rear roof part.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.